Skeletal muscles are voluntary muscles that move your bones. You have control over them, unlike smooth muscle that works on organs or the cardiac muscle of your heart, both of which work without you having to think about them. Skeletal muscle is also called striated muscle because it has a striped appearance. There are several groups of skeletal muscles that move your legs, arm, trunk, neck and face.

Major Muscles of the Upper Limbs

The major muscles of the upper limbs move your humerus (upper arm bone), radius and ulna (lower arm bones) and the bones of the wrist and hand. Deltoid muscles form the caps of your shoulders and move your upper arm in several directions. Triceps brachii forms the back of your upper arm and straightens your elbow. Your biceps brachii forms the front of your upper arm and bends your elbow. Wrist flexors and extensors bend and straighten your wrist, and many small muscles move your hand and finger bones.

Major Muscles of the Trunk

Major muscles of the trunk include the abdominal, back and chest muscles. Rectus abdominus forms the "six pack" of your abdomen and bends your trunk at the waist. The obliques form the sides of your abdomen and twist your trunk. Trapezius, rhomboids and latisimus dorsi form your upper back and help move your shoulders. The pectoral muscles shape your chest and help move your upper arms. Erector spinae muscles straighten your back.

Major Muscles of the Neck and Face

The scalenes and sternocleidomastoids turn and bend your neck forward. Capitis and cervicis muscle groups bend your neck backward. Facial muscles include the muscles of expression that surround your mouth, eyes and nose. The orbicularis oris muscle surrounds your mouth and the buccinator tightens your cheek when you smile. The orbicularis oculi surround the eyes and close your eyelids.